ONALASKA, Wisc. — Skogen’s Festival Foods here has agreed to purchase two Quillin’s stores in LaCrosse, Wis., the companies said. Skogen’s said it would close one Quillin’s store in April so as to build a larger Festival location nearby. The other location would switch from the Quillin’s name to the Festival banner in April. Quillin’s, based in LaCrosse, said it would continue to operate the five stores not sold to Festival. Festival operates 17 stores in Wisconsin.